With the limitation of number of the voltage vectors in Voltage Source Inverter, the reasonable switching table of the traditional direct torque control is not able to be established and the torque ripple is large. A new method based on discrete space vector modulation is proposed to improve this problem in this paper, in which the number of voltage vectors is increased, the value and phase of voltage vectors are more continuous. Also, the different switching tables are established according to the different speed so that the large torque ripple is avoided. The experimental results show this method reduces the torque ripple and current ripple significantly.